When reporters first saw Douglas' racy, form-follows-function
X-3 (photo) Stiletto on the flight line at Edwards, in October 1952, they
were certain they were looking at the shape of things to come. The slender,
needle-nosed, trapezoidal winged airplane looked like it was made for speed...and,
indeed, it was. Douglas had designed it to study high-speed aerodynamic
phenomenon at sustained speeds of up to Mach 2 and to examine the feasibility
employing extremely thin, short-span, low aspect ratio wings on high-performance
aircraft.

Sustained supersonic flight operations would have permitted flight
researchers to acquire much greater amounts of data than could be obtained
with the momentary supersonic episodes attainable with the rocket planes.
The airplane was bold in concept but, unfortunately, the aerodynamic free
thinking of the Douglas design team could not overcome powerplant difficulties
experienced by Westinghouse, whose proposed J46 turbojet engines grew too
large to install in the X-3's extremely slender fuselage. From that point,
the X-3's promise of sustained high-speed flight exploration vanished as
a pair of less-powerful J34 engines were installed just to get the craft
airborne for its first flight at Edwards on October 20, 1952. The sleek
airplane was woefully underpowered and never got close to Mach 2. Indeed,
it was only able to exceed Mach 1 while in a steep dive.